A comparative study of hybrid compensation systems using a multiple feedback control scheme

This thesis is an investigation of hybrid compensation topologies for mitigating load current harmonics, supply and load voltage distortion using a comparison approach. Four hybrid topologies are considered with a hybrid load consisting of current source type and voltage source type nonlinear loads. The compensation systems use the synchronous frame method for harmonic current extraction and propose an extraction scheme for the distortion voltage, which is based on a comparison of the distorted voltage with a fixed reference. The suitability of the multiple feedback loop control scheme was also investigated. It was determined that the scheme is effective in the generation of sinusoidal and distortion components of compensating currents and voltages and hence suitable for active filtering application.;Using the extraction and control schemes, the performance of the compensation systems was examined under different conditions of supply voltage and load currents. The results obtained showed the functionality of the control schemes in the compensation of disturbances caused by non-linear load operations and source end distortions.;A methodical determination of the ratings of the active filters in the hybrid compensators is also presented. The results show that rating curve is a function of the active filter type and the impedance of the passive filter.